This invention relates to an improved centrifuge tube assembly, which enables chemicals or bodily fluids to be effectively separated and aspirated after they have been centrifuged. More particularly, this invention relates to an apparatus that conveniently sequesters platelet-rich plasma for use in surgical and medical procedures.
Platelet-rich blood plasma is required for use in various medical procedures. This blood product is particularly effective due to its growth promoting features, which assist greatly in wound healing and bone regeneration. Presently, blood plasma with a high concentration of platelets is utilized for dental implants and other periodontal procedures, facial reconstruction, oral or maxillofacial surgery and chronic wound care. In order to obtain a required concentration of platelets, a blood sample normally must be centrifuged in order to separate the blood into its component blood products (i.e. plasma, red blood cells and platelets). The platelets, typically in a form of a white xe2x80x9cbuffy coatxe2x80x9d, are then separated from the blood sample and sequestered in concentrated form through aspiration. Conventional aspiration techniques often fail to provide a satisfactory concentration of platelets. Cross-contamination between the constituent products is frequently encountered. We have determined that the need exists for a cost effective apparatus that facilitates the sequestration of platelets while minimizing cross-contamination between blood components.
It is therefore an object of the present invention to provide an improved centrifuge tube assembly that allows chemicals or fluids and primarily blood to be aspirated in discrete components much more effectively and cost efficiently than has been achieved using conventional centrifuge tubes.
It is a further object of this invention to provide a centrifuge tube assembly that permits chemicals and bodily fluids to be separated and individually aspirated with minimal cross-contamination.
It is a further object of this invention to provide a centrifuge tube that is particularly effective for sequestering a high concentration of platelet-rich blood plasma for use in various medical procedures.
It is a further object of this invention to provide a centrifuge tube may be used in various medical and veterinary applications.
This invention features a centrifuge tube assembly having an elongate tubular receptacle and a cap that is removably or permanently engaged with an open upper end of the tubular receptacle. First and second ports are formed in the cap for communicating with an interior of the tubular receptacle. A first aspiration pipe is communicably connected to the first port and a second aspiration pipe is similarly connected to the second port. The first aspiration pipe extends to a point proximate to a lower end of the tubular receptacle such that fluid within the tube may be aspirated through the first aspiration pipe from a lower end of the tubular receptacle. The second aspiration pipe extends downwardly through the tubular receptacle to a level spaced above the lower end of the first aspiration pipe. Fluid located above that level may be aspirated through the second aspiration pipe and the second port.
In a preferred embodiment, the first and second ports comprise Luer(trademark) ports formed through the cap. The first aspiration pipe may extend substantially to the bottom of the tubular receptacle. The second aspiration pipe may extend to a level of approximately 5 ml within the tubular receptacle. The first and second aspiration pipes may be interengaged with the first and second ports in a snug, fitted relationship.
A vent hole may be formed through the cap and into the tubular receptacle for neutralizing pressure within the receptacle. The vent hole may have a diameter of about 1-2 mm.
The aspiration pipes may have diameters of about 3 mm each and may include various lengths in accordance with this invention. The tubular receptacle capable of accommodating varying volumes. Graduated markings may be formed at various desired intervals along the side of the tubular receptacle.
A method of separating blood into constituent blood products using the foregoing assembly is also featured. Initially, a blood sample is introduced into the tubular receptacle and the cap is attached to the receptacle such that the interengaged aspiration pipes are inserted into the tubular receptacle. The blood is then centrifuged for a desired period of time, e.g. 5-7 minutes. This separates the blood into discrete components, which form layers within the tube, i.e. red blood cells at the lower end, yellow plasma proximate the upper end and platelets in the form of a white buffy coat between the red blood cells and plasma. After centrifuging is complete, the red blood cells are aspirated through the first aspiration pipe. This aspiration procedure continues until the boundary between the red blood cells and platelets reaches the bottom of the tube. The apparatus is then centrifuged a second time for an additional period of typically 5-7 minutes. Typically, two discrete layers of blood products remain, the white buffy coat proximate the lower end of the tube and plasma above the buffy coat. The plasma is largely removed by aspirating it through the second aspiration pipe. As a result, platelet-rich plasma remains within the tubular receptacle after the second aspiration is completed. This product is then used as needed for various medical and surgical procedures.
In an alternative version of this invention, a single aspiration port and engaged pipe may be used. The pipe may be slidable or otherwise longitudinally adjustable through a snug opening in the closure. This enables the lower end of the pipe to be positioned at a selected depth in the receptacle such that the lower end is immersed in a corresponding blood or other liquid component. That component may then be aspirated through the pipe.